The present invention relates to an actuator for locating a head such as a magnetic head and also to a disk apparatus such as a storage apparatus using the head locating actuator.
In general, a disk apparatus of the kind mentioned above requires that a head is located, with a high degree of positional accuracy, between adjacent information tracks in the disk, in order to enable enhancement of storage capacity of the disk. To cope with such a demand, various measures have been taken such as rigidification of head carrying structure, provision of a damping mechanism and elimination of disturbance which might affect an actuator which serves as a head locating means.
Japanese Unexamination Patent Publication No. 4-302869 discloses a technique for reducing disturbance caused by a flexible printed circuit (abbreviated as "FPC", hereinafter) attached to the actuator. According to the disclosure, the disturbance is reduced by such an arrangement that FPC is disposed in such a position that the disturbance generated by the FPC, mostly a static reaction force produced by FPC, is substantially nullified when the magnetic head is located substantially midst between the radially outermost and innermost positions which the head takes during recording/reproduction.
The above-described arrangement is effective in diminishing the static reaction force which is generated by the FPC to act as disturbance, but cannot deal with any dynamic reaction force which may be applied to the head.
The actuator to which the FPC is connected moves at a high speed to the target information track position, so that an impact or dynamic force is applied to the FPC to cause it to vibrate. The vibration produces a dynamic reacting force which is transmitted to the actuator to hamper precise positioning of the head. The dynamic reacting force is of such a nature that it is generated even when there is no static reacting force. In order to achieve a high locating precision of the head, therefore, it is necessary to take a suitable measure for reducing dynamic reacting force.